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Are loudspeakers merely commodites? Or do they have (inevitable) personalities?

Are loudspeakers merely commodites? Or do they have (inevitable) personalities?

14-04-2012, 08:48 PM

A post has appeared on the internet which states that 'loudspeakers are indistinguishable under A-B, instantaneous switch over conditions' (no gap between switching from one to another). The writer says that the only way to identify a loudspeaker's personality is to play one pair for perhaps hours, and then to change over to another pair for another long listening session. Can that be true? Doesn't that contradict the Harbeth design approach? Alan says that when he is auditioning a new design he rarely listens to more than a few seconds of music from A, then B then A then B ..... He says he's using the music as a test source, not for pleasure.

What do you actually hear when you play music and without stopping or pausing it, instantaneously change-over the amplifier signal from speaker A to speaker B, positioned side by side. I've never tried to do that. What should I expect? What would it reveal?

Can you let me hear what Alan hears when he instantaneously switches from speaker A to B? Can you put a microphone in the room to record that experience for us? Would that same microphone pick-up differences between level matched amplifiers or CD players being A-B instantaneously compared driving one pair of speakers?

Speakers have to have personalities, they are made of moving parts, cones, tweeters, ribbons, etc, so each one will reproduce sound in its own way, not to mention the cross-over design, as well as the ability to reproduce bass notes at different amplitudes.

Speaker design overall seems to have gotten more interesting (perhaps a bit better, but that is open to debate), but the designer makes them specifically to "speak" a certain way, ie. Harbeths reproduce the voice as most realistically as possible, as well as piano. Other speakers will present something else as per what the designer was planning, or in some cases, opposite to the plan, but time is money and if it sounds ok, then let's market it as something special in the land of sound reproduction.

When doing an A-B instantaneous test, what will be playing? If I switch between one song lyric to the next, will that influence my choice?

If the singer is whispering or screaming will I be fooled?

Is a single tone, E# for example, going to allow me to focus on the sound of the speaker (or amplifier for that matter, depending on the test)?

Will I be fooled by room reflections, because speaker A is voiced differently than B and will the room impact the sound more?

If I am doing this test at home with my comparator, how do I really make the test honest, for me?

An finally, I think I would love to hear what Alan hears when doing the testing. It would be interesting if we had a panel speaker, a Martin Logan, and a big speaker, Tannoy, to compare, then a Harbeth and a Gallo. Sort of like a playoff series when comparing them.

And yes, quick switching. Long listen for comparison makes no sense, as my "ear memory" is about 10 to the power of -10 in length...(i.e. none)

Cheers

George

Comment

In my opinion, I think speakers inherently project traits which invoke more likes/ dislikes compared with any other electronics group so its not a commodity in that sense. With some exposure and experience a frame of reference should emerge, enough to even draw some quick conclusions of them.

How many times do we walk into a shop, listen to a speaker (or look at a television) and form a pretty quick judgement of whether, “we like and can live with it”, “like it with some reservations but can still live with it” or “item can’t be used, intolerable, bombards the senses even after adjusting it”.

If we measure and superimpose criteria of different speakers (of relative similar types to be fair) placed in a similar position* in a same room, the results must surely be different. If we did this, but this time swapped cd players or amps instead (keeping the similar speaker known to never faze an amp) , I'm very sure those traces would exhibit less personality swings.

At certain price points, and getting lower nowadays for most electronics, differences start to diminish. Only in the world of hifi is this reversed (or perceived to be so). As Macjager mentions pianos, most trained ears should be able to tell the difference between a Steinway and a “heavy” Bosendorfer. Electronics are thought to be able to mimic that personality now, even of a Stradivarius.

If personalities can be mimicked are they commoditized by default? I’ve often heard or read of the “BBC sound”, or in the70’s, the American “west coast” and “east coast” speaker sound. This surely must be the nuggets we’re all chasing, and all different, albeit very subtle to some.

Comment

Speakers have to have personalities, they are made of moving parts, cones, tweeters, ribbons, etc, so each one will reproduce sound in its own way...

An finally, I think I would love to hear what Alan hears when doing the testing. It would be interesting if we had a panel speaker, a Martin Logan, and a big speaker, Tannoy, to compare, then a Harbeth and a Gallo. Sort of like a playoff series when comparing them.

I'd also like to do this but we have to be careful and responsible. Our objective here is not to claim outright superiority of speaker design and performance - it's up to you to match your sonic requirements with the thousands of different speakers in the market place. Nor is it our objective to denigrate hard working speaker designers, who, by definition have a customer base large or small for their creations and a valid share of the market.

It would certainly be possible for the microphone to pick-up the difference in sonic signature driving my listening room between any speakers placed in that room, and for you to be able to hear them. I was assuming that you'd be interested in seeing a video (or at least highlights of) the entire set-up and evaluation process. Unfortunately, the sort of speakers you suggest would be difficult to physically disguise and if you could guess their identity I don't think I could justify their introduction into the session. How to handle this sensitive matter?

Comment

DSRANCE is having problems posting using the new forum software and asked me to post the following on his behalf

Please forgive me if I misunderstand the thread contents, but back in the day, we used "comparators" to compare speakers for clients. Not the best way to do it, since the speakers not playing did seem to have a slight negative effect on the absolute quality of the speakers playing, but it was easy to hear different balance and colouration issues, at the time as much in the drive units being used as the boxes they were mounted in (the old KEF B200 for example having a general very slight "cupped hands" kind of tonality irrespective of the speaker models it was used in).

In later years and with smaller speakers, we'd do a general comparator based dem to whittle the candidates down, and then demonstrate the "short-list" individually for the client in our dem rooms.

So, in conclusion, I would say that ALL speakers have a personality of sorts, the end-result for the listener I think, being to select the model that best helps to "suspend disbelief" when listening to the music being produced.

Comment

In regards to my comments about comparing speakers, my main intent was not to denigrate any other speaker, but in fact to be able to compare very different designs. I can see how the playoff quote could be seen as looking for a winner takes all approach, but that is not my intent. Rather how each design type is different and what it brings to the table.

As to disguising them, perhaps the following idea may work: place a screen hung with sheer curtains in front of all of the speakers, the room is made fairly dark, you set up several light stands to the front of the screen, shining at the listening area; the effect on any video camera would be such that you could not distinguish one speaker from the other...something like those spy movies where the good guy has a light shone at him, and from behind it comes an ominous voice: "well Mr. Shaw, sooo, you think you know about hockey do you"...

You may even be able to do this type of lighting set up without using the curtain, and then there could be no accusations of "dulling the sound" due to the introduction of some kind of dampening...

Cheers

George

Comment

Deliberately excessive High Frequencies in a modern 'speaker - a 'sonicualisation' experience

Following this post, I was in the newsagents yesterday flicking through a hifi magazine. By examining the reviewer's published frequency response, I noted for the second time in just a few months a possibly worrying trend in modern speaker design: a cranked-up extreme top end. Both examples are from the same high-profile brand but two different reviews in two different magazines. I do not recollect if it is the same model or not.

For those who can interpret a frequency response plot, it creates the same experience in the mind as looking at a musical score: a magical process whereby you can 'hear' - or more accurately sonically-visualise ('sonicualise'?) - the sonic effect of a boost or cut in the energy in particular frequency bands. I can't read a score so that world is closed to me, but I doubt that many musicians can interpret a frequency response plot; it's all about accumulated experience.

First time around, seeing the frequency response plot so dramatically elevated at around 10kHz I was curious if this was a manufacturing fault, design mistake, a design intention, a reflection of the designer's own latent degraded HF hearing acuity through age or exposure, some obstruction of his ears that attenuated his top end sensitivity, temporary poor health such as a head cold, or a measurement error. But second time around, it's clear that this is a design intention. It's quite absurd to double the sound pressure level around 10kHz. Why would a speaker designer want to bend the recording to be significantly brighter than the artists/producer/recording engineer laid down? The answer must be that it sounds 'right' to him for whatever physiological/marketing reasons he has to justify it, but such a speaker cannot be heralded as truly high-fidelity, whatever glowing praise the reviewer heaps upon it.

So, how does such a boost actually sound? We can easily demonstrate that. I generated some pink noise, which sounds like a soft rushing and selected two 3 second portions and cranked-up the top end to simulate how such a speaker would sound. First you'll hear the flat pink noise, then 3 secs. of boosted top, then return to flat, then 3s. of boosted top again, finally return to flat.

Loading the player ...

Pink noise with HF boost Ex. #1

Now the essential point is this: the inexperienced listener may well initially find the boosted top-end rather attractive. It would be easy to mould his opinion with accompanying comments about listening-out for the 'great clarity', the 'inner detail', the 'high resolution', the 'sparkle and sheen' of music played over such speakers. But that is all a marketing trick.

There is an ugly downside to this: good luck selling the speaker to the inexperienced user - it's even possible that there is a generation of loudspeaker buyers who have crippled their hearing on headphones and to whom such a speaker merely compensates for the self-inflicted hearing degradation they have suffered; to them it sounds 'right' - a very clever marketing ploy. But - taken home and played to others with normal hearing, such a speaker would drive them round the bend with listening fatigue to the point that they could not bear to be in the same room as the speaker playing.

Our human auditory system expects a certain sonic energy balance across the 20-20kHz auditory band through exposure from birth as to how voices and instruments sound. If reproduced sound emphasises or de-emphasises certain sonic bands, our subconscious is soon aware that we are not listening to the real sound, first hand but a manipulated copy of it. That sets up stress in the brain trying to rationalise and characterise this new experience ('it sounds somewhat like a girl's voice but I've never heard a real voice with so much upper tonal emphasis .... so it surely can't be a real girl...?') and detracts from the all-important immersive experience of truly high-fidelity sound at home.

How does this +6dB at 10kHz sound when applied to classical music i.e. if you listened to normal music on speakers exhibiting that much HF elevation, could you hear the boost?

Loading the player ...

Ex. #2 - Orchestral music initially 'flat, but with portion from 23-33 seconds from the start boosted with same HF lift as in Ex.#1. (Ghastly)

Tip 1: listen to the sudden jump in loudness/brightness of the maracas (left channel) when the boost is applied at 23 secs. in
Tip 2: notice that when the boost turns off (at 33 secs.) you are more aware of the reduction in overall HF than of the increase in HF when the boost is applied at 23 secs.

Of all the tricks that are used by loudspeaker designers to create a hi-fi like experience, there is no justification whatsoever for this deliberate manipulation of the reproduced sound. If you see a frequency response curve exhibiting a +6dB (= doubling of sound pressure) hump from about 10kHz upwards, regardless of potentially glowing praise, give it that speaker a wide berth. It is likely to drive you to despair through listening fatigue. How and why a reviewer does not wince when he hooks up the speaker is very disturbing but they now seem to love the cranked-up sound - or they listen with their eyes not ears.

Alan A. ShawDesigner, ownerHarbeth Audio UK

Comment

Comment

What a coincidence! A couple of hours ago while driving with my family I pointed that some radio stations music is rather fatiguing, i.e., the treble seemed to titled to the plus side. No matter how much I meddle with the bass and treble knobs I cant get it right.

Maybe, it is not only the loudspeakers' designers employ this trick but radio stations too could be deliberating making their sound to be bright besides the loudness war. Just a thought.

ST

p.s. Before I forget again, congratulations on the launching of the new M30.1.

Comment

&quot;I don't care about the measurements.... design me a speaker that SELLS!&quot;

Sometimes the obvious is overlooked. I've just realised that what has been obvious to me for thirty years may be a complete surprise to you.

In these recent threads here and also here we have been looking at the subjective sonic effect that results from arranging for the middle frequencies of a loudspeaker (or indeed any element in the hi-fi chain from the mic to the loudspeaker itself) to be boosted over the 'average' energy output across the entire audio band. This extra energy is the result of either some characteristics of the bass/midrange unit itself and/or the design of the internal crossover/equaliser and/or the shape of the cabinet. However it originates, the designer and his marketing colleagues consider the resulting 'projected' midrange to be sonically 'right'. They certainly have the means to achieve a more neutral presentation across the audio band but chose not to. So the point is that an elevated midrange is deliberate, intentional and implemented for commercial reasons. In short, it's the 'sound that sells'.

Thumbing through these little HiFiChoice, Loudspeakers review summary books from the 1980s researching my response for the above threads, it occurred to me just how many of the speakers reviewed exhibited that elevated midrange, which as I've stated, can only be the result of a deliberate design decision. So, I thought I'd scan a selection which, like the Heybrook HB1 we looked at, have a similar measured frequency response and most likely then, the 'sound that sells' in the middle registers. There are 13 examples I've picked at random. They are mainly speakers of shoebox size and 2-3 times that size; say, the P3 > C7 size range.

There are two things we should consider. First, two of the speakers in the group - both shoebox size - were very deliberately designed to have all middle and no bass. The designer's avowed intention was for a 'fast' sound (i.e. all middle frequencies) and to use the inevitable reinforcing bass-boost that the close proximity of the speaker against a hard, undamped domestic wall would bring. The theory was that 'the wall can do the work' and that placed on a shelf or really close to the rear wall, the wall-gain would prop-up the extremely weak bass the speaker generated itself and, speaker + wall boost would work together so that bass/mid would be subjectively back in-balance for the listener. I could never see how that could work: no two rooms and no two walls would behave the same. The LS3/5a concept of designing for a flat 'anechoic response' and accepting a gentle additional boost at LF from the room seems to give a much more natural and satisfactory listening experience at home. Anyway, the all-mid, no-bottom cult had its rabid devotees, so at least some listeners were delighted. Secondly: I don't know if this strong middle personality boost represents the current state of affairs - frequency response plots are so rarely published these days, but if the design process is (still) driven by commercial goals, why shouldn't contemporaneous home hi-fi speakers have the same ear-catching boost? Neither the rules of commerce nor human hearing has changed in 20-30 years that's for sure!

In a few days I'll scan what we could identify as the neutral 'BBC balance' where all frequencies are reproduced across the audio band without undue emphasis. It goes without saying that to the great unwashed, the projected humped-up, louder middle will sound far more engaging and the neutral BBC balance washed-out in comparison. Conversely, those who record and balance sound professionally would find the elevated mid of the typical domestic 'hi-fi' speaker mildly amusing and utterly useless as a precision instrument!

As I mentioned, if you get hooked on this cranked-up middle, it will very quickly become your internal frame of reference. It's not normally especially objectionable; it's just not what you would hear at the microphones. You may really fall for the breathy immediacy of vocals, the over-vivid 'being there' experience of the performers not on a stage in-line with or behind the speakers, but right there on the rug in front of you! We've covered this all in detail here.

Comment

... As I mentioned, if you get hooked on this cranked-up middle, it will very quickly become your internal frame of reference. It's not normally especially objectionable; it's just not what you would hear at the microphones. You may really fall for the breathy immediacy of vocals, the over-vivid 'being there' experience of the performers not on a stage in-line with or behind the speakers, but right there on the rug in front of you!...

From the same 1980s source books, I've scanned a selection of speakers which do not exhibit the marked hump-up in loudness in the middle frequencies. These include one or two 'BBC monitors' as you would expect.

So I've added these flatter speakers to the PDF so we now have pages 1 and 2 as before, the elevated midrange resulting in a subjectively more immediate or forward presentation, followed by pages 3 and 4 with the measurably flatter responses. The point I hope this conveys is that regardless of nationality, size of box number of drive units or even drive unit cone technology, the speaker designer has total control over the energy output of the speaker. If he is aiming at a 'BBC balance', all instruments are given equal loudness and the designer needs to craft a fairly flat frequency response, at least on axis across the primary audi band - say, 100Hz to 10kHz.

If the speaker designer has commercial pressures to create a speaker that is more ear-grabbing, he would be wise to do some market research as to what music his target customers like. Once he knows that, he will know which frequency bands could be boosted (never suppressed) to emphasise those instruments or vocals. He will have adapted his speaker to the tastes of his customers. If the customer mainly listens to electric bass guitar, a flat midrange and treble may not give the most satisfactory listening experience. If the listener is a fan of the high-hat or cymbal, then it could be legitimately argued that a boosted extreme top may give a more vivid listen. Is that a crime? No, no more than a shoe designer adorning his creations to draw attention to them or a car designer adding fancy wheels or a loud exhaust. The sole issue is that if the loudspeaker is tailored to particular music or consumer taste, that personality is locked into the product and in the hands of a different consumer or application with different tastes and requirements, it may sound terrible or not be usable at all.

But if - as in the case of a BBC monitor - in one hour the loudspeaker is being used to monitor the reading of a sombre obituary, the next a historic jazz recording, the next a live classical broadcast and the next, a radio drama where the entire picture is painted by and with sound then a flat, natural, even sound output across the entire audio band is a must have.

Comment

I'd only add that there are speakers out there today with just the kind of balance you describe and provide plots for - a rising responce into the "glare" frequencies followed by a slight shelving down into the tweeter, this latter set to approximately the 500Hz mean level, but then this balance is marketed as "flat" and "neutral," meaning that anything that really IS flat then sounds wrong.

I was almost guitly of this in the late 70's and early 80's, although I do hope that by the time our paths first crossed some years later, that I'd grown out of this by then.....

Comment

Are you saying Dave that some (or even many) studio monitors are voiced with this "glare hump" even as their makers claim them to be flat?

I'm sure that you'll recognise the most famous "professional monitor speaker" of all time - the white coned NS10 - picture attached. This speaker is installed in perhaps the majority of pop music studios worldwide, and has been the reference standard for playback for twenty years. The thinking is that 'if it sounds good on the NS10s it will sound good on anything at home or in the car ...' and it is the final arbiter of the recorded mix in the opinion of many musicians and their engineers.

You wouldn't seriously expect such a speaker to have a flat (blue line in previous PDF) would you? It couldn't emulate a typical user's equipment if it did have .... from recollection, I measured one and it had a huge peak in the response around 900Hz. That peak, carefully positioned in frequency and loudness, had a most interesting sonic characteristic.

Article dissecting the NS10 '... we trace its history, and investigate why a monitor whose sound has been described as "horrible" became an industry standard...' here. The measurements are considerably smoother and at a higher peak frequency than the one I measured and the overall response is broadly of the elevated nature of those on pages 1 and 2 of my PDF (above the red flat line) - see attachment to post 10/11 above.

You can, of course, follow the widely adopted advice to 'improve' the sound of the NS10 by (this is no joke) applying tissue paper over the tweeter. You can read about that here.

There is also a thorough overview of many studio monitors with frequency response measurements on the attached PDF. Some interesting things to note ....

Page 6, Graph 15 and 16: HHB Circle 3P and 5A monitors (designed by me) had to have an elevated upper-mid to meet the client's specification. They sold extremely well to the home-studio market and this overall response shape was a deliberate design choice. 10+ years after production ended, we are still supporting the C5 as their owners love them! The step responses (page 18) are amongst the cleanest.

Page 7, Graph 38: Yamaha NS10M

If you have been following the analysis of transmission line speakers (TLs) here, you will appreciate that there is an inescapable problem with TLs namely, sound emanating from the open end of the pipe reinforces the woofer output at some frequencies and abruptly cancels the sound at others. This gives an instantly recognisable 'glitch' - or series of glitches - in the frequency response plot of the entire speaker at a distance as the woofer and pipe fight each other and consequently the overall summed loudness goes up and down across the midrange. If you skim through the (black line) frequency response plots in pages 5-7, you will be able to pick out the one TL design simply by looking for the characteristic abrupt glitches starting around 100Hz and proceeding serially up to the 1000Hz range. As we have seen, all independent source-data (software models, actual measurements of real speakers) indicates that this cancellation problem is an inescapable reality of TLs. The TL design has a unique construction which as we can see from pages 5-7 gives a unique measurable response. All the other speakers (as far as I can tell from the frequency response curves) have conventional sealed or vented boxes, with a basically smooth response below about 500Hz. That's because they do not have an open mouth and avoid the anti-phase sound wave that such a large orifice inevitably permits out into the room.

Note: the only way to remove these glitches is to completely stuff the TL pipe with wool or similar. Having done that, the response would revert to a smooth sealed (or perhaps vented) box now without the glitches, but at enormous wasted cost and effort. A madcap idea would be to engineer the TL with a motorised cat-flap over the mouth driven by a computer which samples the sound. Depending upon the prominence of certain notes in the music, the flap would rapidly spring open or shut, either letting the pipe vent the note if in-phase with the woofer or slamming it tightly shut when the note from the pipe is antiphase with the woofer. Then, the TLs currently unavoidable problems might just become tolerable across at least a narrow bandwidth.